Irenaeus tells us something of great importance about the very early Church, and that is that there was very much uniformity and consistency in what the churches taught and that the churches that the apostles themselves ministered in and to were still present and that should a question of doctrine arise, these genuinely apostolic churches could be consulted for definitive answers.
Irenaeus Against Heresies, Book III
Chap. IV. The Truth Is to Be Found Nowhere Else but in the Catholic Church, the Sole Depository of Apostolical Doctrine. Heresies Are of Recent Formation, and Cannot Trace Their Origin up to the Apostles.
1. Since therefore we have such proofs, it is not necessary to seek the truth among others which it is easy to obtain from the Church; since the apostles, like a rich man [depositing his money] in a bank, lodged in her hands most copiously all things pertaining to the truth: so that every man, whosoever will, can draw from her the water of life. For she is the entrance to life; all others are thieves and robbers. On this account are we bound to avoid them, but to make choice of the thing pertaining to the Church with the utmost diligence, and to lay hold of the tradition of the truth. For how stands the case? Suppose there arise a dispute relative to some important question among us, should we not have recourse to the most ancient Churches with which the apostles held constant intercourse, and learn from them what is certain and clear in regard to the present question? For how should it be if the apostles themselves had not left us writings? Would it not be necessary, [in that case,] to follow the course of the tradition which they handed down to those to whom they did commit the Churches?
It is absolutely essential for readers to understand that when this work was written, sometime between the years of 182-188, the Catholic church was NOT the Roman Catholic Church that we have today and that none of the doctrines that distinguish the Roman Catholic Church from our Protestant churches had yet been introduced into the Church. Gnosticism, however, was attempting to make inroads into the Church and Irenaeus was especially concerned with refuting the heresies of Gnosticism and keeping them out of the Church. Irenaeus very strictly adhered to the teachings of the genuinely apostolic churches that were still present in his day, and those teachings included the teaching of conditional security. I am going to quote a fairly lengthy portion from the writings of Irenaeus so that you can see clearly that not only did Irenaeus teach conditional security, but that he understood Paul to have taught it, and so that you can see for yourselves how Irenaeus defended the doctrine of conditional security.
Irenaeus Against Heresies, Book IV
Chap. XXVII The Sins of the Men of Old Time, Which Incurred the Displeasure of God, Were, by His Providence, Committed to Writing, That We Might Derive Instruction Thereby, and Not Be Filled with Pride. We Must Not, Therefore, Infer That There Was Another God Than He Whom Christ Preached; We Should Rather Fear, Lest the One and the Same God Who Inflicted Punishment on the Ancients, Should Bring Down Heavier upon Us.
1. As I have heard from a certain presbyter, who had heard it from those who had seen the apostles, and from those who had been their disciples, the punishment [declared] in Scripture was sufficient for the ancients in regard to what they did without the Spirits guidance. For as God is no respecter of persons, He inflicted a proper punishment on deeds displeasing to Him. As in the case of David, when he suffered persecution from Saul for righteousness sake, and fled from King Saul, and would not avenge himself of his enemy, he both sung the advent of Christ, and instructed the nations in wisdom, and did everything after the Spirits guidance, and pleased God. But when his lust prompted him to take Bathsheba, the wife of Uriah, the Scripture said concerning him, Now, the thing (sermo) which David had done appeared wicked in the eyes of the Lord; and Nathan the prophet is sent to him, pointing out to him his crime, in order that he, passing sentence upon and condemning himself, might obtain mercy and forgiveness from Christ: And [Nathan] said to him, There were two men in one city; the one rich, and the other poor. The rich man had exceeding many flocks and herds; but the poor man had nothing, save one little ewe-lamb, which he possessed, and nourished up; and it had been with him and with his children together: it did eat of his own bread, and drank of his cup, and was to him as a daughter. And there came a guest unto the rich man; and he spared to take of the flock of his own ewe-lambs, and from the herds of his own oxen, to entertain the guest; but he took the ewe-lamb of the poor man, and set it before the man that had come unto him. And Davids anger was greatly kindled against the man; and he said to Nathan, As the Lord liveth, the man that hath done this thing shall surely die (filius mortis est): and he shall restore the lamb fourfold, because he hath done this thing, and because he had no pity for the poor man. And Nathan said unto him, Thou art the man who hast done this. And then he proceeds with the rest [of the narrative], upbraiding him, and recounting Gods benefits towards him, and [showing him] how much his conduct had displeased the Lord. For [he declared] that works of this nature were not pleasing to God, but that great wrath was suspended over his house. David, however, was struck with remorse on heating this, and exclaimed, I have sinned against the Lord; and he sung a penitential psalm, waiting for the coming of the Lord, who washes and makes clean the man who had 499 been fast bound with [the chain of] sin. In like manner it was with regard to Solomon, while he continued to judge uprightly, and to declare the wisdom of God, and built the temple as the type of truth, and set forth the glories of God, and announced the peace about to come upon the nations, and prefigured the kingdom of Christ, and spake three thousand parables about the Lords advent, and five thousand songs, singing praise to God, and expounded the wisdom of God in creation, [discoursing] as to the nature of every tree, every herb, and of all fowls, quadrupeds, and fishes; and he said, Will God whom the heavens cannot contain, really dwell with men upon the earth? And he pleased God, and was the admiration of all; and all kings of the earth sought an interview with him (quaerebant faciem ejus) that they might hear the wisdom which God had conferred upon him. The queen of the south, too, came to him from the ends of the earth, to ascertain the wisdom that was in him: she whom the Lord also referred to as one who should rise up in the judgment with the nations of those men who do hear His words, and do not believe in Him, and should condemn them, inasmuch as she submitted herself to the wisdom announced by the servant of God, while these men despised that wisdom which proceeded directly from the Son of God. For Solomon was a servant, but Christ is indeed the Son of God, and the Lord of Solomon. While, therefore, he served God without blame, and ministered to His dispensations, then was he glorified: but when he took wives from all nations, and permitted them to set up idols in Israel, the Scripture spake thus concerning him: And King Solomon was a lover of women, and he took to himself foreign women; and it came to pass, when Solomon was old, his heart was not perfect with the Lord his God. And the foreign women turned away his heart after strange gods. And Solomon did evil in the sight of the Lord: he did not walk after the Lord, as did David his father. And the Lord was angry with Solomon; for his heart was not perfect with the Lord, as was the heart of David his father. The Scripture has thus sufficiently reproved him, as the presbyter remarked, in order that no flesh may glory in the sight of the Lord.
2. It was for this reason, too, that the Lord descended into the regions beneath the earth, preaching His advent there also, and [declaring] the remission of sins received by those who believe in Him. Now all those believed in Him who had hope towards Him, that is, those who proclaimed His advent, and submitted to His dispensations, the righteous men, the prophets, and the patriarchs, to whom He remitted sins in the same way as He did to us, which sins we should not lay to their charge, if we would not despise the grace of God. For as these men did not impute unto us (the Gentiles) our transgressions, which we wrought before Christ was manifested among us, so also it is not right that we should lay blame upon those who sinned before Christs coming. For all men come short of the glory of God, and are not justified of themselves, but by the advent of the Lord, they who earnestly direct their eyes towards His light. And it is for our instruction that their actions have been committed to writing, that we might know, in the first place, that our God and theirs is one, and that sins do not please Him although committed by men of renown; and in the second place, that we should keep from wickedness. For if these men of old time, who preceded us in the gifts [bestowed upon them], and for whom the Son of God had not yet suffered, when they committed any sin and served fleshly lusts, were rendered objects of such disgrace, what shall the men of the present day suffer, who have despised the Lords coming, and become the slaves of their own lusts? And truly the death of the Lord became [the means of] healing and remission of sins to the former, but Christ shall not die again in behalf of those who now commit sin, for death shall no more have dominion over Him; but the Son shall come in the glory of the Father, requiring from His stewards and dispensers the money which He had entrusted to them, with usury; and from those to whom He had given most shall He demand most. We ought not, therefore, as that presbyter remarks, to be puffed up, nor be severe upon those of old time, but ought ourselves to fear, lest perchance, after [we have come to] the knowledge of Christ, if we do things displeasing to God, we obtain no further forgiveness of sins, but be shut out from His kingdom. And therefore it was that Paul said, For if [God] spared not the natural branches, [take heed] lest He also spare not thee, who, when thou wert a wild olive tree, wert grafted into the fatness of the olive tree, and wert made a partaker of its fatness.
3. Thou wilt notice, too, that the transgressions of the common people have been described in like manner, not for the sake of those who did then transgress, but as a means of instruction unto us, and that we should understand that it is one and the same God against whom these 500 men sinned, and against whom certain persons do now transgress from among those who profess to have believed in Him. But this also, [as the presbyter states,] has Paul declared most plainly in the Epistle to the Corinthians, when he says, Brethren, I would not that ye should be ignorant, how that all our fathers were under the cloud, and were all baptized unto Moses in the sea, and did all eat the same spiritual meat, and did all drink the same spiritual drink: for they drank of that spiritual rock that followed them; and the rock was Christ. But with many of them God was not well pleased, for they were overthrown in the wilderness. These things were for our example (in figuram nostri), to the intent that we should not lust after evil things, as they also lusted; neither be ye idolaters, as were some of them, as it is written: The people sat down to eat and drink, and rose up to play. Neither let us commit fornication, as some of them also did, and fell in one day three and twenty thousand. Neither let us tempt Christ, as some of them also tempted, and were destroyed of serpents. Neither murmur ye, as some of them murmured, and were destroyed of the destroyer. But all these things happened to them in a figure, and were written for our admonition, upon whom the end of the world (saeculorum) is come. Wherefore let him that thinketh he standeth, take heed lest he fall.
